I got the rebuilt Power module back from the rebuilder and reinstalled it.
It's been a while since i posted on this topic so I will remind those reading that the main problem I have been chasing is that i can't get air out of the AC or the heater ducts-even though the heat/ac vacuum solenoid is working. Today, I found out why.
I installed the newly rebuilt Module but it did not make a difference, even though I could clearly see the arm moving in response to the temperature wheel movement. BUMMER!
I don't know what inspired me to do it, but I took the power module off again and looked inside the hole in the heater plenum with the Power module removed. There I saw a flat piece of what looks like flat rubber insulation (about 7 inches by 5 inches), part of which had come loose from its proper place on the plenum wall and had placed itself squarely in the way of the air path. I glued it back and tried the system: VOILA. I have air from the AC vents and Heat from the Heater.
The frustration I have experienced over the last several months has made this triumph all the more exciting. Next up: Aim the headlights.